1. Field of the Invention
This invention is related to a ladder step platform that will provide a stable support surface for the user of a ladder. The invention is also related to ladder step platforms that can be adjusted for use on different ladders and for use when the ladder is positioned at different orientations.
2. Description of the Prior Art
The prior art suggests that a ladder step platform can be added to ladders by employing a J-shaped strap or hook extending over one of the ladder rungs. The lower portion of these prior art ladder step platforms can engage either a lower rung or the ladder rails. These ladder step platforms provide a support surface area, on which a user of the ladder may stand, that is larger than the rung surface area. Representative examples of ladder step platforms, which extend beyond an inclined ladder, are shown in U.S. Pat. Nos. 2,486,783 and 3,294,197. Another example in which the ladder step platform is recessed relative to the ladder is shown in U.S. Pat. No. 5,836,420.
Although these prior art devices appear to be easy to use, there are significant differences between these devices and the ladder step platform comprising the preferred embodiment of this invention. Each of these prior art devices consists of a rigid assembly that can be mounted on a ladder. Since the straps or hooks are draped over the rungs between the ladder rails, the same device can be used on ladders having different widths. However, these devices are not adjustable and the width of the platform may not be equal to the width of the ladder on which it is to be used. Since the platform can only be as wide as the smallest ladder with which it is to be used, the available space for larger ladders may be less than desired. Furthermore since the straps or hooks are draped over the rungs between the ladder rails, they can interfere with latches that allow adjustment in the length of extension ladders. These straps and hooks could also interfere with the rope that is used to raise and lower the sections of an extension ladder. It is not possible to attach these prior art ladder step platforms on the outside of the ladder rails, as allowed by the preferred embodiment of this invention, where they will be no interference in the manipulation of the extension ladder. The hooks or straps of these prior art devices are also not attached to the ladder, and it appears that they can be inadvertently dislodged.
The instant invention is mounted on a ladder by inserting a support rod through hollow rungs of the type used on conventional metal and fiberglass extension ladders or fiberglass ladders or any other ladders having hollow rungs. The ladder step platform of the preferred embodiment of this invention cannot therefore be inadvertently dislodged, but it will also not interfere with adjustment hardware on conventional extension ladders. The instant invention can also be adjusted for use with ladders in which the spacing of the rails is different.
U.S. Pat. No. 6,109,391 does disclose a concept in which a scaffold can be supported by spaced ladders, and a mounting device is attached to a rod extending through hollow ladder rungs. However, this device employs a multi-link structure that also appears to be attached to a rod extending through a lower rail. This scaffold is mounted between the ladders and the structure on which the ladder is mounted so that a user can only stand between the ladders and there is no provision for use of a ladder step platform on either of the ladders used to support the scaffold.
Unlike these prior art devices, the ladder step platform according to this invention is also collapsible allowing assembly of the components on site and simplifying shipping and handling of this device when not in use. Furthermore it can be fabricated from simple metal stampings and can use conventional fasteners.